The present invention relates to an apparatus responsive to the amount of refrigerant flow in a refrigerant circulating system for refrigerating purposes, for example, which is designed for use in air conditioners such as automobile coolers.
Refrigerant circulating systems which have heretofore been used for refrigerating purposes are usually of the type in which a compressor, a condenser, a pressure regulator and an evaporator are interconnected by a refrigerant pipeline and a refrigerant is sealed in the system. For use with this type of systems several methods have been proposed for the purpose of detecting the amount of refrigerant flow to prevent a decrease in the cooling capacity of the refrigerator or damage to the refrigerator due to the leakage of the refrigerant. These known methods include the use of refrigerant flow detecting apparatus designed to electrically detect a change in the dielectric constant in the refrigerant passage, for example, disclosed in Japanese Laid-Open Publication No. 16743/77.
However, these known refrigerant flow detecting apparatus of the dielectric constant responsive type are disadvantageous in that a change in the dielectric constant is small as compared with a change in the amount of refrigerant flow and this requires an increase in the size of a dielectric constant sensor, an increase in the amplification factor and accuracy of the electric circuit and the like, thus requiring an increase in the size and complexity of the apparatus or the use of expensive components.